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.\" Copyright 2019 Joyent, Inc.
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.Dd July 22, 2019
.Dt MAC_ALLOC 9F
.Os
.Sh NAME
.Nm mac_alloc ,
.Nm mac_free
.Nd allocate and free mac registration structures
.Sh SYNOPSIS
.In sys/mac_provider.h
.Ft "mac_register_t *"
.Fo mac_alloc
.Fa "uint_t mac_version"
.Fc
.Ft void
.Fo mac_free
.Fa "mac_register_t *mregp"
.Fc
.Sh INTERFACE LEVEL
illumos DDI specific
.Sh PARAMETERS
.Bl -tag -width Fa
.It Fa mac_version
An integer corresponding to the version of the MAC interface that the
device driver was built against.
.It Fa mregp
A pointer to an allocated mac_register_t structure that was obtained
from calling the
.Fn mac_alloc
function.
.El
.Sh DESCRIPTION
The
.Fn mac_alloc
and
.Fn mac_free
routines are used to allocate and free the structures used to register a
device driver with
.Xr mac 9E .
The device driver should call
.Fn mac_alloc
with the value of
.Dv MAC_VERSION
to indicate the current version of the MAC framework that it supports.
The device driver will be returned an instance of a
.Xr mac_register 9S
structure which it can then use to call
.Xr mac_register 9F .
For more information on the order of events, see the
.Sx Initializing MAC Support
section of
.Xr mac 9E .
.Pp
When the driver is done with the
.Xr mac_register 9S
structure, it must call the
.Fn mac_free
function to release any memory associated with the handle.
.Pp
After the driver has called
.Xr mac_register 9F
during its
.Xr attach 9E
entry point, the
.Xr mac_register 9S
structure is no longer needed and can be freed.
.Sh CONTEXT
The
.Fn mac_alloc
and
.Fn mac_free
routines are generally called from the context of a device driver's
.Xr attach 9E
entry point; however, they may be called from both
.Sy user
and
.Sy kernel
context.
.Sh RETURN VALUES
Upon successful completion, the
.Fn mac_alloc
function will return a pointer to an allocated
.Sy mac_register_t
structure that can be filled in by the driver.
Otherwise,
.Dv NULL
is returned to indicate that the structure could not be allocated.
The most common cause for this is that the value of
.Fa mac_version
is not supported by the kernel.
.Sh SEE ALSO
.Xr attach 9E ,
.Xr mac 9E ,
.Xr mac_register 9F ,
.Xr mac_register 9S
